Tracking system, tracking device and tracking method

ABSTRACT

A tracking system includes a first device and a second device. The second device comprises an optical module, an ultrasonic module and a processor. The optical module is configured to capture image data in a first detection field. The ultrasonic module is configured to collect ultrasonic data in a second detection field different from the first detection field. The processor is configured to determine a relative position of a target device relative to the tracking device in a third detection field according to the image data and the ultrasonic data. The third detection field is larger than the first detection field and larger than the second detection field.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Application Ser.No. 62/439,902, filed on Dec. 29, 2016, which is herein incorporated byreference.

BACKGROUND Field of Invention

Present disclosure relates to a tracking system, a tracking device, anda tracking method. More particularly, present disclosure relates to atracking system, a tracking device, and a tracking method usingultrasounds.

Description of Related Art

Nowadays, more and more electronic devices are capable of measuringrelative distances by cameras. However, detection via cameras is limitedby the field of views (FOVs) of the cameras. The detection accuracy canbe influenced by the distortion when the FOV is high. On the other hand,camera-based detection requires high computation powers.

Apparently, using camera solely to measure distances in a long time isnot an ideal approach. Therefore, improvements are required.

SUMMARY

Aiming to solve aforementioned problems, present disclosure provides atracking system, a tracking device, and a tracking method.

The disclosure provides a tracking system. The tracking system comprisesa first device and a second device. The second device comprises anoptical module, an ultrasonic module and a processor. The optical moduleis configured to capture image data in a first detection field. Theultrasonic module is configured to collect ultrasonic data in a seconddetection field different from the first detection field. The processoris configured to determine a relative position of the first devicerelative to the second device in a third detection field according to atleast one of the image data and the ultrasonic data. The third detectionfield is larger than the first detection field and larger than thesecond detection field.

Another aspect of disclosure is to provide a tracking device. Thetracking device comprises an optical module, an ultrasonic module and aprocessor. The optical module is configured to capture image data in afirst detection field. The ultrasonic module is configured to collectultrasonic data in a second detection field different from the firstdetection field. The processor is configured to determine a relativeposition of a target device relative to the tracking device in a thirddetection field according to at least one of the image data and theultrasonic data. The third detection field is larger than the firstdetection field and larger than the second detection field.

Another aspect of present disclosure is to provide a tracking method.The method comprises following steps: capturing, by an optical module ofthe second device, image data in a first detection field; collecting, byan ultrasonic module of the second device, ultrasonic data in a seconddetection field different from the first detection field; anddetermining, by a processor of the second device, a relative position ofthe first device relative to the second device in a third detectionfield according to at least one of the image data and the ultrasonicdata, in which the third detection field is larger than the firstdetection field and larger than the second detection field.

It is to be understood that both the foregoing general description andthe following detailed description are by examples, and are intended toprovide further explanation of the disclosure as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

Present disclosure can be more fully understood by reading the followingdetailed description of the embodiment, with reference made to theaccompanying drawings as follows:

FIG. 1 is a schematic diagram of a tracking system illustrated accordingto one embodiment of present disclosure;

FIG. 2A is a schematic diagram of a tracking system of the trackingsystem illustrated according to one embodiment of present disclosure;

FIG. 2B is a schematic diagram of a tracking system and the detectionfields of the tracking system illustrated according to one embodiment ofpresent disclosure;

FIG. 3 is a flow chart of a tracking method illustrated according to oneembodiment of present disclosure;

FIG. 4 is a schematic diagram shows a processor of a tracking systemaccording to one embodiment of present disclosure;

FIG. 5A is a schematic diagram showing the tracking system operates insome optical detection fields according to one embodiment of presentdisclosure;

FIG. 5B is a schematic diagram showing the tracking system operates insome optical detection fields according to one embodiment of presentdisclosure;

FIG. 6A is a schematic diagram shows the tracking system operates insome ultrasonic detection fields according to the embodiment of FIG. 5A;

FIG. 6B is a schematic diagram shows the tracking system operates insome ultrasonic detection fields according to the embodiment of FIG. 5B;and

FIG. 7 is a schematic diagram shows the tracking system operates incombined detection fields according to one embodiment of presentdisclosure.

DETAILED DESCRIPTION

Reference will now be made in detail to the present embodiments of thedisclosure, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers are used in thedrawings and the description to refer to the same or like parts.

As used herein, the terms “comprising,” “including,” “having,” and thelike are to be understood to be open-ended, i.e., to mean including butnot limited to.

Reference throughout the specification to “one embodiment” or “anembodiment” means that a particular feature, structure, implementation,or characteristic described in connection with the embodiment isincluded in at least one embodiment of the present disclosure. Thus,uses of the phrases “in one embodiment” or “in an embodiment” in variousplaces throughout the specification are not necessarily all referring tothe same embodiment. Furthermore, the particular features, structures,implementation, or characteristics may be combined in any suitablemanner in one or more embodiments.

FIG. 1 is a schematic diagram of a tracking system illustrated accordingto one embodiment of present disclosure. In the embodiment, the trackingsystem TRS includes a first device 100 and a second device 200. Thefirst device 100 can be a hand-held controller of the tracking systemTRS. The second device 200 can be a head-mounted display device, inwhich the second device 200 is configured to track the motion of thefirst device 100 with respect to the second device 200 when the trackingsystem TRS is in operation. It is noted, in some embodiment, a user canwear the second device 200 on his/her head and hold the first device 100in his/her head. In this case, when the user moves the first device 100with his/her head, the second device 200 can track the motion of thefirst device 100 and execute certain operations according to the motionof the first device 100.

As shown in FIG. 1, in the embodiment, the first device 100 includes aninertial measurement unit 110. The inertial measurement unit 110 is asensor comprises gyros and accelerometers configured to detect angularaccelerations and accelerations along at least six axes when the firstdevice 100 is in operation. When the first device 100 is moved by theuser, the inertial measurement unit 110 can detect angular accelerationsand accelerations along these six axes of the first device 100, in whichthe angular accelerations and the accelerations can be used to generatean orientation of the first device 100.

As shown in FIG. 1, in the embodiment, the second device 200 includes anoptical module 210, an ultrasonic module 220, a processor 230, and adisplay 240. The optical module 210, the ultrasonic module 220 and thedisplay 240 are all electrically coupled to the processor 230. Theoptical module 210 can be a combination of some optical sensors andmicroprocessors that is configured to capture image data in a firstdetection field. When the first device 100 is in first detection field,the image data captured by the optical module 210 may containinformation regarding the first device 100. The ultrasonic module 220can be a combination of some ultrasonic transceivers andmicroprocessors. The ultrasonic module 220 is configured to sendultrasounds toward a second detection field and collect ultrasoundreflections from the second detection field to generate ultrasonic data.When the first device 100 is in second detection field, the ultrasonicdata collected by the ultrasonic module 220 may contain informationregarding the first device 100.

In the embodiment, the processor 230 includes, for example, a singleprocessing unit and a combination of plurality microprocessorselectrically connected to internal or external memory via buses, inwhich the internal or external memory can be volatile or non-volatilememories. The processor 230 is configured to fetch a set of instructionsfrom the internal or external memories, to execute the set ofinstructions, and to perform predetermined processes according to theinstructions. The predetermined processes will be explained below.

In the embodiment, the optical module 210 can send the image data to theprocessor 230, and the ultrasonic module 220 can send the ultrasonicdata to the processor 230 as well. After the processor 230 receives theimage data and the ultrasonic data, the processor 230 can generate anintegration data according to the image data and the ultrasonic data. Itis noted, whether the first device 100 is detected in the firstdetection field or the second detection field, the processor 230 candetermine a relative position of the first device 100 relative to thesecond device 200 based on the integration data. It should be noted, theintegration data contain information regarding both the first and thesecond detection field, so a third detection field covered by theintegration data is a detection field larger than the first detectionfield or the second detection field.

In the embodiment, the display 240 is electrically coupled to theprocessor 230. The processor 230 is further configured to sendinformation about a simulated environment to the display 240 so that thedisplay 240 can output a partial view of the simulated environment tothe user based on the information. It should be noted, said simulatedenvironment can be a computer technology that generates realisticimages, sounds and other sensations to simulate the user's presence in avirtual or imaginary environment. Said simulated environment includesvirtual reality environment, augmented reality environment or mixedreality environment. In the embodiment, when the user is wearing thesecond device 200, the display 240 can display the partial view of thesimulated environment to the user. Through the partial view displayed bythe display 240, the user can immerse in the simulated environment.

In some embodiment, the inertial measurement unit 110 of the firstdevice 100 can communicate with the processor 230 via a signaltransceiver (not shown in figure) settled on the first device 100, inwhich the signal transceiver can be a radio frequency transceiver or aninfrared transceiver. Therefore, the inertial measurement unit 110 cansend the orientation of the first device 100 to the processor 230. Inthis case, the processor 230 can illustrate a virtual objectcorresponding to the first device 100 in the simulated environmentaccording to a combination of the relative position and the orientation.For example, if the user is playing a virtual reality game aboutadventures, the virtual object being displayed in the game environmentcan be a virtual hand holding a virtual sword, in which the virtualobject is illustrated based on the relative position of first device 100and the orientation of first device 100. As such, by tracking therelative position of first device 100 and the orientation of firstdevice 100, the processor 230 can illustrate the virtual hand at theposition that the first device 100 is located, and illustrate thevirtual sword pointing to the orientation that the first device 100 ispointed.

FIG. 2A is a schematic diagram of a tracking system of the trackingsystem illustrated according to one embodiment of present disclosure. Inthe embodiment, a detail configuration of the second device 200 in thetracking system TRS of FIG. 1 is illustrated in FIG. 2A. The figureshows an above view of the second device 200, which is a head-mounteddisplay device. As shown in FIG. 2A, the optical module 210 shown inFIG. 1 includes two optical sensors, which are a first optical sensor211 and a second optical sensor 212. It can be seen that the firstoptical sensor 211 and the second optical sensor 212 are disposed on afront surface of the second device 200 in parallel. As shown in FIG. 2A,the ultrasonic module 220 shown in FIG. 1 includes ultrasonictransceivers, in which the six ultrasonic transceivers are grouped astwo ultrasonic arrays. Three among the six ultrasonic transceivers, theultrasonic transceivers 221-223, are grouped as a first ultrasonicarray, which is disposed on the left lateral of the second device 200.Another three ultrasonic transceivers, the ultrasonic transceivers224-226, are grouped as a second ultrasonic array, which is disposed onthe right lateral of the second device 200.

It is noticed that, an number of the ultrasonic transceivers in thefirst ultrasonic array or the second ultrasonic array is not limited tothree transceivers as shown in FIG. 2A. In another embodiment, a numberof the ultrasonic transceivers in the first ultrasonic array or thesecond ultrasonic array can include more than three transceivers toincrease accuracy of ultrasonic detection.

FIG. 2B is a schematic diagram of a tracking system and the detectionfields of the tracking system illustrated according to one embodiment ofpresent disclosure. In the embodiment, a combination of the firstoptical sensor 211 and the second optical sensor 212 has an opticaldetection field ODF. It means that the first optical sensor 211 and thesecond optical sensor 212 are both configured to capture image data inthe optical detection field ODF. Whether the first device 100 mentionedin FIG. 1 is detected by the first optical sensor 211 or the secondoptical sensor 212, the image data obtained by the optical module 210may contain information regarding the first device 100.

In the foregoing embodiment, the optical module 210 includes the firstoptical sensor 211 and the second optical sensor 212. It can be seen inthe figure, the combination of the first optical sensor 211 and thesecond optical sensor 212 is capable of detecting the first device 100in the optical detection field ODF. However, the configuration of theoptical module 210 is not limited thereto. It some embodiments, theoptical module 210 may comprise a single optical sensor disposed at thecenter of the front end of the second device, in which the singleoptical sensor has an optical detection. When the first device 100mentioned in FIG. 1 is detected in the optical detection field, theimage data obtained by the optical module 210 may contain informationregarding the first device 100.

In the embodiment, in can be seen in the figure, the first ultrasonictransceiver 221, the second ultrasonic transceiver 222 and the thirdultrasonic transceiver 223 are in combination to collect ultrasound datain a first ultrasonic detection field UDF1. On the other side, thefourth ultrasonic transceiver 224, the fifth ultrasonic transceiver 225and the sixth ultrasonic transceiver 226 are in combination to collectultrasound data in a second ultrasonic detection field UDF2. In theembodiment, the ultrasonic detection fields UDF1-UDF2 are in combinationto form the second detection field as mentioned in the embodiment ofFIG. 1. Whether the first device 100 mentioned in FIG. 1 is detected inany of the ultrasonic detection fields UDF1-UDF2, the ultrasonic datacollected by the ultrasonic module 220 may contain information regardingthe first device 100.

It is noted, as mentioned in the embodiment of FIG. 1, the processor 230of the second device 200 can retrieve the ultrasonic data collected bythe ultrasonic module 220 and the image data obtained by the opticalmodule 210. In this case, as shown in FIG. 2B, when the first device 100is located in the optical detection field ODF, it is the optical module210 that tracks the position of the first device 100. When the firstdevice 100 is located in the ultrasonic detection fields UDF1-UDF2, itis the ultrasonic module 220 that tracks the position of the firstdevice 100. When the first device 100 is located in the overlappedfields of the ultrasonic detection fields UDF1-UDF2 and the opticaldetection field ODF, both the optical module 210 and the ultrasonicmodule 220 can track the position of the first device 100. It is to say,the combination of the optical module 210 and the ultrasonic module 220provides availability for the processor 230 to track the position of thefirst device 100 in a range that is larger than the optical detectionfield ODF and the ultrasonic detection fields UDF1-UDF2.

It is noted, although the detection accuracy and efficiency of theoptical sensor is good, it can produce high electricity consumption andhigh computational workloads. Moreover, the field of view limitation ofthe optical sensor can be another problem. Therefore, a combination ofthe optical sensors and ultrasonic transceivers can generate a largerdetection field with lower electricity consumption and computationalworkloads. On the other hand, if the second device 200 is applied as ahead-mounted display to output simulated environments, the virtualobject corresponding to the first device 100 will be displayed insimulated environments when the first device 100 is detected in theoptical detection fields. It is known, the users will be sensitive tothe slight changes when the image data being captured in the opticaldetection fields is changing, so it requires higher accuracy forillustrating the positions of the first device 100 in the opticaldetection fields. On the other hand, in the fields that the users cannotobserve, present disclosure provides an approach to track the firstdevice 100 with ultrasounds in these fields. Therefore, the accuracy andefficiency of the entire system can be increased.

FIG. 3 is a flow chart of a tracking method illustrated according to oneembodiment of present disclosure. In the embodiment, the tracking method300 can be executed by the tracking system TRS shown in foregoingembodiments, and the references to the embodiments are hereinincorporated. In the embodiment, the steps of the tracking method 300will be listed and explained in detail in following segments.

Step S301: capturing, by an optical module of a device, image data in afirst detection field. As described in the embodiment of FIG. 1, FIG. 2Aand FIG. 2B, the optical module 210 of the second device 200 includestwo optical sensors, and each of the optical sensors 211-212 isconfigured to capture image data in the optical detection field ODF. Theimage data captured by the optical module 210 can be sent to theprocessor 230 of the second device 200.

Step S302: collecting, by an ultrasonic module of the device, ultrasonicdata in a second detection field. As described in the embodiment of FIG.1, FIG. 2A and FIG. 2B, the ultrasonic module 220 of the second device200 includes six ultrasonic transceivers 221-226. Each of the ultrasonictransceivers 221-223 is configured to capture ultrasonic data in thefirst ultrasonic detection field UDF1, respectively. Each of theultrasonic transceivers 224-226 is configured to capture ultrasonic datain the second ultrasonic detection field UDF2, respectively. Theultrasonic data captured by the ultrasonic module 220 can be sent to theprocessor 230 of the second device 200.

Step S303: determining, by a processor of the device, a relativeposition of another device relative to the device in a third detectionfield according to the image data and the ultrasonic data, wherein thethird detection field is larger than the first detection field andlarger than the second detection field. As described in the embodimentof FIG. 1, FIG. 2A and FIG. 2B, when the processor 230 receives theimage data and the ultrasonic data, the processor 230 can determine arelative position between the first device 100 and the second device 200based on the image data and the ultrasonic data. It is to say, presentdisclosure provides a solid approach to track the first device 100 in anomnidirectional range by combining the optical module 210 and theultrasonic module 220. The processes that the processor 230 determinesthe relative position will be described in following paragraphs.

FIG. 4 is a schematic diagram shows a processor of a tracking systemaccording to one embodiment of present disclosure. The figureillustrates the detail configuration of the processor 230 as mentionedin foregoing embodiments. As such, the references to the foregoingembodiments are herein incorporated. The processor 230 includes anoptical position solver 231, an acoustic position solver 232, an angleweighted filter 233, a distance weighted filter 234, an orientationcalculator 235, and a fuse state machine 236. These solvers, filters,calculators, and state machine are operation units of the processor 230.When the processor 230 executes the instructions fetched from thememories, these operation units can perform predetermined processesdescribed below. In some embodiments, the solvers, filters, calculators,and state machine are programs executed by the processor 230. When theprocessor 230 executes the instructions fetched from the memories, theseprograms can perform predetermined processes described below.

As mentioned, when the first device 100 is detected in the opticaldetection field ODF, the image data captured by the first optical sensor211 or the second optical sensor 212 contains the information regardingthe position of the first device 100. It is noted, in some embodiments,the first optical sensor 211 and the second optical sensor 212 areconfigured to recognize an optical detectable area settled on the firstdevice 100, when the optical detectable area of the first device 100 isdetected in the optical detection fields ODF, the image data captured bythe optical sensors 211-212 may include the position the first device100.

In the embodiment, the optical position solver 231 is configured toreceive the image data captured by the first optical sensor 211 and thesecond optical sensor 212. Then, the optical position solver 231 cangenerate an optical-solved position of the first device 100 accordingthe image data.

In the embodiment, the angle weighted filter 233 is configured toperform a weight calculation to the optical-solved position generated bythe optical position solver 231. As mentioned, the first optical sensor211 and the second optical sensor 212 form the optical detection fieldODF. When first device 100 is located in the optical detection fieldODF, the first device 100 can be detected by the first optical sensor211 or the second optical sensor 212. However, it is noted, the opticalsensor has its limitations. Typically, if the first device 100 islocated at the middle of the optical detection field ODF, the firstoptical sensor 211 or the second optical sensor 212 can detect the firstdevice 100 with high accuracy. However, if the first device 100 islocated around the edge of the optical detection field ODF, the accuracythat the first optical sensor 211 or the second optical sensor 212detects the first device 100 is relatively lower. Therefore, the weightcalculation is applied to the optical-solved positions generated by theoptical position solver 231 to ameliorate the accuracy of theoptical-solved positions being detected. In the embodiment, the angleweighted filter 233 can assign an optical weight to the optical-solvedposition in the weight calculation.

FIG. 5A is a schematic diagram showing the tracking system operates insome optical detection fields according to one embodiment of presentdisclosure. It can be seen in FIG. 5A that, in the embodiment, the firstdevice 100 is detectable at a first position within an overlapped fieldOLF between the optical detection field ODF and the first ultrasonicdetection fields UDF1. In the embodiment, the first optical sensor 211and the second optical sensor 212 can capture first image data, and theoptical position solver 231 can generate a first optical-solved positionof the first device 100 according the first image data. And the angleweighted filter 233 can calculate a first angle θ1 between a normal axisof the optical module 210 (which includes the first optical sensor 211and the second optical sensor 212) and a line extended from the opticalmodule 210 to the first device 100. In this case, the angle weightedfilter 233 can determine a first optical weight for the firstoptical-solved position according to the first angle θ1.

FIG. 5B is a schematic diagram showing the tracking system operates insome optical detection fields according to one embodiment of presentdisclosure. As shown in FIG. 5B, in the embodiment, the first device 100is detectable at a second position within the overlapped field OLFbetween the optical detection field ODF and the first ultrasonicdetection fields UDF1 as well. In the embodiment, the first opticalsensor 211 and the second optical sensor 212 can capture second imagedata, and the optical position solver 231 can generate a secondoptical-solved position of the first device 100 according the secondimage data. The angle weighted filter 233 can calculate a second angleθ2 between the normal axis of the optical module 210 (which includes thefirst optical sensor 211 and the second optical sensor 212) and anotherline extended from the optical module 210 to the first device 100. Inthis case, the angle weighted filter 233 can determine a second opticalweight for the second optical-solved position according to the firstangle θ1.

Comparing FIG. 5A with FIG. 5B, it is clear that the first angle 81 issmaller than the second angle 82, which means the first device 100 shownin FIG. 5B is much closer to the edge of the optical detection fieldODF. In this case, when the weight calculation is performed, the firstoptical weight being determined by the angle weighted filter 233 in theembodiment of FIG. 5A will be larger than the second optical weightbeing determined by the angle weighted filter 233 in the embodiment ofFIG. 5B. For example, the first optical weight being assigned to thefirst optical-solved position can be 0.70, and the second optical weightbeing assigned to the second optical-solved position can be 0.30. In theembodiment of FIG. 5A, the angle weighted filter 233 can multiply thefirst optical-solved position with the first optical weight to generatea weighted optical-solved position for the first device 100 in theweight calculation. In the embodiment of FIG. 5B, the angle weightedfilter 233 can multiply the second optical-solved position with thesecond optical weight to generate another weighted optical-solvedposition for the first device 100 in the weight calculation. Clearly,because the first optical weight is larger than the second opticalweight, the weighted optical-solved position being generated in theembodiment of FIG. 5A would be larger than the weighted optical-solvedposition being generated in the embodiment of FIG. 5B. It is to say, ifthe first device 100 is being detected far from the normal axis of theoptical module 210, the angle weighted filter 233 determines a relativesmaller optical weight for the optical-solved position of the firstdevice 100.

However, it is noted, the assignation of the optical weights tooptical-solved positions shown in above embodiments are merely examples,the values of the optical weights are subject to change depends ondifferent requirements of the system.

Reference is made to FIG. 4. In the embodiment of FIG. 4, when the firstdevice 100 is detected in each of the ultrasonic detection fieldsUDF1-UDF2, the ultrasonic data captured by the corresponding ultrasonictransceivers 221-226 may contain the information regarding the positionof the first device 100. In the embodiment, the acoustic position solver232 is configured to receive the ultrasonic data captured by theultrasonic transceivers 221-226. Similar to the optical position solver231, the acoustic position solver 232 is configured to generateacoustic-solved positions of the first device 100 according theultrasonic data collected by the ultrasonic transceivers 221-226. Forexample, when the first device 100 is located in the detection field ofthe ultrasonic array disposed on the left lateral of the second device200, the acoustic position solver 232 can generate an acoustic-solvedposition according the ultrasonic data collected by the ultrasonictransceivers 221-223.

In the embodiment, the distance weighted filter 234 is configured toperform a weight calculation to the acoustic-solved position generatedby the acoustic position solver 232. Since the ultrasonic transceivers221-223 form the first ultrasonic detection field UDF1, when the firstdevice 100 is in the first ultrasonic detection fields UDF1, each of theultrasonic transceivers 221-223 can detect the first device 100. Theweight calculation applied by the distance weighted filter 234 is toameliorate the accuracy of the acoustic-solved positions being detected.In the embodiment, the distance weighted filter 234 can assign anacoustic weight corresponding to the acoustic-solved position in theweight calculation.

FIG. 6A is a schematic diagram shows the tracking system operates insome ultrasonic detection fields according to the embodiment of FIG. 5A.The figure is illustrated to explain the weight calculation of thedistance weighted filter 234. As shown in FIG. 6A, the first device 100is ultrasonically detectable at the first position (the same position asshown in FIG. 5A) within the overlapped field OLF between the opticaldetection field ODF and the first ultrasonic detection field UDF1. Inthe embodiment, the ultrasonic transceivers 221-223 collect firstultrasonic data from the first ultrasonic detection field UDF1, and thefirst ultrasonic data is sent to the acoustic position solver 232.According to the first ultrasonic data, the acoustic position solver 232can calculate a first distance D1 between the first device 100 and thefirst ultrasonic transceiver 221, a second distance D2 between the firstdevice 100 and the second ultrasonic transceiver 222, and a thirddistance D3 between the first device 100 and the third ultrasonictransceiver 223. According to the distances D1-D3, the acoustic positionsolver 232 can obtain a first acoustic-solved position for the firstdevice 100. However, the ultrasonic transceiver also has itslimitations. Typically, if the first device 100 is located at theposition closer to the ultrasonic transceivers 221-223, theacoustic-solved position being obtained by the acoustic position solver232 is more accurate. On the other hand, if the first device 100 islocated at the position far from the ultrasonic transceivers 221-223,the acoustic-solved position being obtained by the acoustic positionsolver 232 is relatively lower. Therefore, the weight calculation isapplied to the acoustic-solved positions generated by the acousticposition solver 232 to ameliorate the accuracy of the acoustic-solvedpositions being detected.

It can be seen in the FIG. 6A that the first distance D1 is shorter thanthe second distance D2, and the second distance D2 is shorter than thethird distance D3. In this case, in the weight calculation, the distanceweighted filter 234 determines a first acoustic weight for the firstacoustic-solved position based on the average distance from the firstdevice 100 to the ultrasonic transceivers 221-223.

FIG. 6B is a schematic diagram shows the tracking system operates insome ultrasonic detection fields according to the embodiment of FIG. 5B.The figure is illustrated to explain the weight calculation of thedistance weighted filter 234 as well. As shown in FIG. 6B, the firstdevice 100 is ultrasonically detectable at the second position (the sameposition as shown in FIG. 5B) within the overlapped field OLF betweenthe optical detection field ODF and the first ultrasonic detectionfields UDF1. In the embodiment, the ultrasonic transceivers 221-223collect second ultrasonic data from the first ultrasonic detection fieldUDF1, and the second ultrasonic data is sent to the acoustic positionsolver 232. According to the second ultrasonic data, the acousticposition solver 232 can calculate a fourth distance D4 between the firstdevice 100 and the first ultrasonic transceiver 221, a fifth distance D5between the first device 100 and the second ultrasonic transceiver 222,and a sixth distance D6 between the first device 100 and the thirdultrasonic transceiver 223. According to the distances D4-D6, theacoustic position solver 232 can obtain a second acoustic-solvedposition for the first device 100. As mentioned, the ultrasonictransceiver also has its limitations. Therefore, the weight calculationis applied to the second acoustic-solved position generated by theacoustic position solver 232 to ameliorate the accuracy of theacoustic-solved positions being detected.

It can be seen in FIG. 6B that the fourth distance D4 is shorter thanthe fifth distance D5, and the sixth distance D6 is shorter than thefifth distance D5. In this case, in the weight calculation, the distanceweighted filter 234 determines a second acoustic weight for the secondacoustic-solved position based on the average distance from the firstdevice 100 to the ultrasonic transceivers 221-223 as well.

Comparing FIG. 6A with FIG. 6B, it is clear that the average distance ofthe distances D1-D3 is longer than the average distance of the distancesD4-D6, which means the first device 100 shown in FIG. 6B is much closerto ultrasonic transceivers 221-223 than it is in FIG. 6A. In this case,when the weight calculation is performed, the first acoustic weightbeing determined by the distance weighted filter 234 in the embodimentof FIG. 6A will be smaller than the second acoustic weight beingdetermined by the distance weighted filter 234 in the embodiment of FIG.6B. For example, the first optical acoustic being assigned to the firstacoustic-solved position can be 0.30, and the second acoustic weightbeing assigned to the second acoustic-solved position can be 0.70. Inthe embodiment of FIG. 6A, the distance weighted filter 234 can multiplythe first acoustic-solved position with the first acoustic weight togenerate a weighted acoustic-solved position for the first device 100 inthe weight calculation. In the embodiment of FIG. 6B, the distanceweighted filter 234 can multiply the second acoustic-solved positionwith the second acoustic weight to generate another weightedacoustic-solved position for the first device 100 in the weightcalculation. Clearly, because the first acoustic weight is smaller thanthe second acoustic weight, the weighted acoustic-solved position beinggenerated in the embodiment of FIG. 6A would be smaller than theweighted acoustic-solved position being generated in the embodiment ofFIG. 6B. It is to say, if the first device 100 is being detected farfrom the ultrasonic module 220, the distance weighted filter 234determines a relative smaller acoustic weight for the acoustic-solvedposition of the first device 100.

It is noted, the assignation of the weights to acoustic-solved positionsshown in above embodiment is merely an example, the values of theacoustic weights are subject to change depends on different requirementsof the system.

As mentioned in the embodiment of FIG. 1, the inertial measurement unit110 can be used to detect an orientation of the first device 100. In theembodiment of FIG. 4, the orientation calculator 235 of the processor230 is configured to retrieve the orientation of the first device 100detected by the inertial measurement unit 110. When the orientation ofthe first device 100 is retrieved, the orientation calculator 235 cansend the orientation to the fuse state machine 236. In the same manner,when the angle weighted filter 233 generates the weighted optical-solvedposition, the weighted optical-solved position is sent to the fuse statemachine 236. When the distance weighted filter 234 generates theweighted acoustic-solved position, the weighted acoustic-solvedposition, is sent to the fuse state machine 236.

In the embodiment of FIG. 4, the fuse state machine 236 is configured tocalculate the weighted optical-solved position and the weightedacoustic-solved position to generate a fused position. Since the opticalmodule 210 and the ultrasonic module 220 are configured to obtain theimage data and the ultrasonic data in the same timeline, so the weightedoptical-solved position generated by the angle weighted filter 233 andweighted acoustic-solved position generated by the distance weightedfilter 234 can be combined to generate the fused position correctly.

It is noted, whether the first device 100 is located in the opticaldetection field ODF or the ultrasonic detection fields UDF1-UDF2, aslong as some of the optical sensors 211-212 and the ultrasonictransceivers 221-226 can detect the first device 100, the fuse statemachine 236 can generate the fused position corresponding to the firstdevice 100. More specifically, in one case, when the first device 100can only be detected in the optical detection field ODF, theoptical-solved position generated by the optical position solver 231 canbe directly sent to the fuse state machine 236 without being weighted,and the fuse state machine 236 can generate the fused position accordingto the optical-solved position and the orientation of the first device100. In another case, when the first device 100 can only be detected inthe first ultrasonic detection field UDF1, the acoustic-solved positiongenerated by the acoustic position solver 232 can be directly sent tothe fuse state machine 236 without being weighted, and the fuse statemachine 236 can generate the fused position according to theacoustic-solved position and the orientation of the first device 100.And, if the first device 100 can be detected in the overlapped fieldOLF, the fuse state machine 236 can generate the fused position asmentioned in foregoing embodiments.

In some embodiments, the fused position corresponding to the firstdevice 100 can be feedback to the optical position solver 231, theacoustic position solver 232, the angle weighted filter 233, and thedistance weighted filter 234. As such, since the optical position solver231 and the acoustic position solver 232 have already received the fusedposition that indicates the previous position of the first device 100,the optical position solver 231 and the acoustic position solver 232 cancalculate the following optical-solved positions and the acoustic-solvedposition in higher accuracy.

FIG. 7 is a schematic diagram shows the tracking system operates incombined detection fields according to one embodiment of presentdisclosure. The figure is illustrated to explain an approach to generatethe optical-solved position in foregoing embodiments. In the embodiment,the weighted acoustic-solved position is feedback, by the distanceweighted filter 234, to the optical position solver 231. For example, asshown in FIG. 7, when the first device 100 is entering, from the firstultrasonic detection field UDF1, to the overlapped field OLF between thefirst ultrasonic detection field UDF1 and the optical detection fieldODF, the weighted acoustic-solved position is feedback to the opticalposition solver 231. When the optical position solver 231 calculates theoptical-solved position according to the image data acquired by thefirst optical sensor 211 and the second optical sensor 212, the opticalposition solver 231 can determine the optical-solved position within arange originated from the weighted acoustic-solved position. It shouldbe noted, in the same manner, when the first device 100 is moving fromanother ultrasonic detection field into the overlapped field betweenthat ultrasonic detection field and any of the optical detection field,the weighted acoustic-solved position will be feedback to the opticalposition solver 231 as well, and the optical position solver 231 willdetermine the optical-solved position within a range originated from theweighted acoustic-solved position. It is to say, the feedback is a wayto narrow down the possibilities of the optical-solved position when thefirst device 100 is moving from the ultrasonic detection fieldsUDF1-UDF2 to the optical detection field ODF.

It is noted, in the overlapped field between the ultrasonic detectionfields UDF1-UDF2 and the optical detection field ODF, the accuracy ofboth the optical-solved positions and the acoustic-solved positions arerelative lower; therefore, present disclosure provides an approach tocombine both the results of the optical-solved positions and theacoustic-solved positions to generate better results. Typically, whenthe first device 100 is moving from the ultrasonic detection fieldsUDF1-UDF2 into the optical detection field ODF, the first device 100 canget into the optical detection field ODF from many possible directions.Therefore, it is difficult for the optical module 210 of the seconddevice 200 to capture the first device 100 in the optical detectionfield ODF fast, and sometimes the user may even notice the loss oftracking. As such, present disclosure provides an approach for theoptical module 210 to narrow down the potential optical-solved positionsbased on received acoustic-solved positions. Therefore, when the firstdevice 100 is moving from the ultrasonic detection fields UDF1-UDF2 intothe optical detection field ODF, with the acoustic-solved position, theoptical module 210 can generate the optical-solved position of the firstdevice 100 immediately.

As described above, the tracking system and the tracking method can beused to combine different optical sensors and ultrasonic transceivers tofrom an omnidirectional detection field. When the target of thedetection is detected by several sensors or transceivers, the processorcan perform the weigh calculation to improve the accuracy whengenerating the optical-solved positions and acoustic-solved positions.Moreover, when the target of the detection is moving from the ultrasonicdetection fields to the optical detection fields, the feedback of theacoustic-solved positions makes the generation of the optical-solvedpositions faster.

Although the present disclosure has been described in considerabledetail with reference to certain embodiments thereof, other embodimentsare possible. Therefore, the spirit and scope of the appended claimsshould not be limited to the description of the embodiments containedherein.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the structure of the presentdisclosure without departing from the scope or spirit of the disclosure.In view of the foregoing, it is intended that the present disclosurecover modifications and variations of this disclosure provided they fallwithin the scope of the following claims.

What is claimed is:
 1. A tracking system, comprising: a first device;and a second device, comprising: an optical module, configured tocapture image data in a first detection field; an ultrasonic module,configured to collect ultrasonic data in a second detection fielddifferent from the first detection field; and a processor, configured todetermine a relative position of the first device relative to the seconddevice in a third detection field according to at least one of the imagedata and the ultrasonic data, wherein the third detection field islarger than the first detection field and larger than the seconddetection field, wherein the processor is configured to calculate afirst weighted position by a first weight according to the image dataand a second weighted position according to the ultrasonic data, theprocessor is configured to calculate the relative position of the firstdevice according to the first weighted position and the second weightedposition when the first device is simultaneously detected in the firstdetection field and the second detection field, wherein the ultrasonicmodule comprises at least three ultrasound transceivers, the processoris configured to calculate at least three distances from each of the atleast three ultrasonic transceivers to the first device according to theultrasonic data, the processor comprises an acoustic position solver,the acoustic position solver is configured to generate anacoustic-solved position of the first device according to the at leastthree distances, the processor calculates the acoustic-solved positionwith a second weight to generate the second weighted position, whereinthe second weight is negative correlated to an average distance of theat least three distances.
 2. The tracking system of claim 1, wherein thefirst device is a controller and the second device is a head mounteddisplay, and the second device is configured to display a simulatedenvironment.
 3. The tracking system of claim 2, wherein the first devicecomprises: an inertial measurement unit configured to detect anorientation of the first device, wherein the orientation of the firstdevice is sent to the processor, the processor illustrates a virtualobject corresponding to the first device in the simulated environmentaccording to the relative position and the orientation.
 4. The trackingsystem of claim 1, wherein the optical module comprises at least twooptical sensors, the processor comprises an optical position solver, theoptical position solver is configured to generate an optical-solvedposition of the first device according to the image data captured by theat least two optical sensors, the processor calculates theoptical-solved position with the first weight to generate the firstweighted position.
 5. The tracking system of claim 4, wherein theprocessor calculates an angle between a normal axis of the at least twooptical sensors and a line extending from a position between the atleast two optical sensors to the first device, the first weight isnegative correlated to the angle.
 6. The tracking system of claim 1,wherein the first detection field and the second detection field arepartially overlapped; and when the second weighted position of the firstdevice is entering the overlapped field, the processor generates thefirst weighted position within a range originated from the secondweighted position.
 7. A tracking device, comprising: an optical module,configured to capture image data in a first detection field; anultrasonic module, configured to collect ultrasonic data in a seconddetection field different from the first detection field; and aprocessor, configured to determine a relative position of a targetdevice relative to the tracking device in a third detection fieldaccording to at least one of the image data and the ultrasonic data,wherein the third detection field is larger than the first detectionfield and larger than the second detection field, wherein the processoris configured to calculate a first weighted position according to theimage data and a second weighted position according to the ultrasonicdata, the processor is configured to calculate the relative position ofthe target device according to the first weighted position and thesecond weighted position when the target device is simultaneouslydetected in the first detection field and the second detection field,wherein the ultrasonic module comprises at least three ultrasoundtransceivers, the processor calculates at least three distances fromeach of the at least three ultrasonic transceivers to the target deviceaccording to the ultrasonic data, the processor comprises an acousticposition solver, the acoustic position solver is configured to generatean acoustic-solved position of the target device according to the atleast three distances, the processor calculates the acoustic-solvedposition with a second weight to generate the second weighted position,wherein the second weight is negative correlated to an average distanceof the at least three distances.
 8. The tracking device of claim 7,wherein the first detection field and the second detection field arepartially overlapped; and when the second weighted position of the firstdevice is entering the overlapped field, the processor generates thefirst weighted position within a range originated from the secondweighted position.
 9. A tracking method for tracking a first device by asecond device, comprising: capturing, by an optical module of the seconddevice, image data in a first detection field; collecting, by anultrasonic module of the second device, ultrasonic data in a seconddetection field different from the first detection field; determining,by a processor of the second device, a relative position of the firstdevice relative to the second device in a third detection fieldaccording to at least one of the image data and the ultrasonic data,wherein the third detection field is larger than the first detectionfield and larger than the second detection field; calculating, by theprocessor, a first weighted position by a first weight according to theimage data and a second weighted position according to the ultrasonicdata; calculating, by the processor, the relative position of the firstdevice according to the first weighted position and the second weightedposition when the first device is simultaneously detected in the firstdetection field and the second detection field; calculating, by theprocessor, at least three distances from at least three ultrasonictransceivers of the ultrasonic module to the first device according tothe ultrasonic data; generating, by an acoustic position solver of theprocessor, an acoustic-solved position of the first device according tothe at least three distances; and calculating, by the processor, theacoustic-solved position with a second weight to generate the secondweighted position, wherein the second weight is negative correlated toan average distance of the at least three distances.
 10. The trackingmethod of claim 9, further comprising: displaying, by a display of thesecond device, a simulated environment; receiving, by the processor, anorientation of the first device; and illustrating, by the processor, avirtual object corresponding to the first device in the simulatedenvironment according to the relative position and the orientation. 11.The tracking method of claim 9, further comprising: generating, by anoptical position solver of the processor, an optical-solved position ofthe first device according to the image data captured by at least twooptical sensors of the optical module; and calculating, by theprocessor, the optical-solved position with the first weight to generatethe first weighted position.
 12. The tracking method of claim 11,further comprising: calculating, by the processor, an angle between anormal axis of the at least two optical sensors and a line extendingfrom a position between the at least two optical sensors to the firstdevice, wherein the first weight is negative correlated to the angle.13. The tracking method of claim 9, further comprising: when the secondweighted position of the first device is entering an overlapped fieldbetween the first detection field and the second detection field,generating, by the processor, the first weighted position within a rangeoriginated from the second weighted position.